Isotope separation process

A method of separating the isotopes of an element, said method being applied to a gaseous compound of said element, said method comprising subjecting the molecules of said compound to IR radiation at a predetermined frequency by means of an IR laser, said gaseous compound being irradiated by said IR laser at a power density of at least 10.sup.4 watts per cm.sup.2 per torr pressure of said gaseous compound for a time of between 10.sup.-.sup.10 and 5.times.10.sup.-.sup.5 seconds and wherein a second gas is present along with said gaseous compound, said second gas partial pressure being at least 5 times the partial pressure of said gaseous compound, whereby the molecules containing the lighter isotope or isotopes are preferentially excited and absorb more than one quanta of IR radiation, subjecting said gaseous mixture to radiation at the second predetermined frequency within the visible or ultraviolet spectrum, said second predetermined frequency being selected to convert said excited molecules to a form whereby they may be separated from the nonexcited molecules, and separating said converted molecules.